The invention relates to a variable valve train of a combustion engine for applying a load to two equally acting gas exchange valves for each cylinder of the combustion engine, wherein a switchable valve train element with an outer part and an inner part that can move relative to each other is allocated to each of the two gas exchange valves, wherein these parts can be selectively connected to each other by means of an associated coupling slide mechanism, so that when they are coupled, a large travel and when they are decoupled, a relatively smaller or zero travel of the gas exchange valve is realized, wherein the valve train further comprises a control shaft on which a control cam is applied to each coupling slide mechanism, and this control cam at least indirectly contacts an outer end face of its coupling slide mechanism for its displacement in one direction.
A valve train according to the class is disclosed in WO 2015/181264 A1. This is described as a variable finger lever drive for valve lift switching. A group of two equally acting gas exchange valves of a cylinder is here equipped with identical finger levers. Each of the finger levers has, for its support element-side end, a piston extending past this end as a coupling slide mechanism. A control cam of a control shaft is allocated to each piston, wherein this control shaft can be rotated by an electric motor. The two control cams do have a rigid arrangement on the control shaft but are offset in phase relative to each other. By rotating the control shaft in one direction, ultimately 4 lift modes and thus 4 total gas exchange cross sections can be achieved for each cylinder.
A disadvantage in the prior art specified above, however, is the “rigid” and non-variable sequence of the switching states. Thus, in the worst case, for example, in the event of abrupt load changes in the combustion engine, the control shaft must first “switch” “step-by-step” until it reaches the desired switching states.